Question

如何在 C#中实现 OPC 数据访问

Answer 1

public virtual void OnReadComplete(System.Int32 dwTransid, //异步读完成触发 System.Int32 hGroup, System.Int32 hrMasterquality, System.Int32 hrMastererror, System.Int32 dwCount, int[] phClientItems, object[] pvValues, short[] pwQualities, OpcRcw.Da.FILETIME[] pftTimeStamps, int[] pErrors) public virtual void OnWriteComplete ( System.Int32 dwTransid , //异步写完成触发 System.Int32 hGroup , System.Int32 hrMastererr , System.Int32 dwCount , int[] pClienthandles , int[] pErrors )
public virtual void OnCancelComplete(System.Int32 dwTransid, System.Int32 hGroup) //取消特定操作触发 public virtual void OnDataChange(Int32 dwTransid, Int32 hGroup, //订阅方式下读触发
IA&DT Service & Support
Page 16-47
Int32 hrMasterquality, Int32 hrMastererror, Int32 dwCount, int[] phClientItems, object[] pvValues, short[] pwQualities, OpcRcw.Da.FILETIME[] pftTimeStamps, int[] pErrors)
问题 3：运行时，有时会弹出 Cross-thread operation not valid 错误，这是 C#中 对控件继承性的一种严格要求，在调试时会出现，可以做如下处理。 在 Form 的.ctor 中，InitealizeComponent 语句做如下处理:
public Form1() { InitializeComponent(); Control.CheckForIllegalCrossThreadCalls = false; }